1. Field of the Description
The present invention relates, in general, to displays providing a three dimensional (3D) effect without use of special glasses such as, but not limited to, a Pepper's Ghost display, and, more particularly, to displays (or display assemblies) and display methods that are adapted to provide a borderless, self-contained Pepper's Ghost illusion without allowing a viewer to see or identify the beam combiner or a support/frame for such a beam combiner.
2. Relevant Background
There are numerous settings where it is desirable to create a unique visual display. For example, theme or amusement parks may include rides or walk-through attractions where guests (or “viewers”) are entertained by a unique visual effect or illusion. Pepper's Ghost is an illusionary technique used by magicians, by ride or attraction designers, and others to produce a 3D illusion of a latent or ghost-like image. Using a simple piece of plate glass and special lighting techniques, conventional Pepper's Ghost systems can make objects appear and disappear within a scene or a room.
Generally, these systems include a main room or scene that is readily viewed by a viewer and also include a hidden room that is not directly visible to the viewer. Both rooms are typically identical in their physical structure except that the hidden room may include additional objects or characters such as a ghost or other character. A large piece of glass or a half-silvered mirror may be situated between the viewer and the scene at an angle, such as at about 45 degrees. When the main room is lit and the hidden room is darkened, the viewer only sees the main room as the hidden room does not reflect from the glass. The sheet of glass is itself hard to see as it typically is quite large so that it extends across the entire view of the main room.
Pepper's Ghost (e.g., the character in the hidden room) then becomes very visible to the viewer when the entire hidden room or portions such as the ghost or other character are brightly lit. Since only a portion of the light cast upon the ghost or other objects in the hidden room is reflected from the glass, the reflected images appear as latent or ghostly images relative to the objects in the main room, e.g., the reflected images or images superimposed in the visible room may appear to float. The Pepper's Ghost image is a 3D image that may be a still image or animation may be provided such as with animatronics providing the “ghost” or by placing a live actor in the hidden room. The image has a definitive location in the set and behaves with correct parallax, focus, and vergence cues; however, it does not exhibit occlusion. In a broad sense, the Pepper's Ghost systems may be thought of as a method of displaying 3D images that can be viewed without the use of headgear or glasses on the part of the user.
FIG. 1 illustrates a traditional layout for a Pepper's Ghost display assembly 100 for use in creating a 3D display 150 for a viewer 102. The assembly 100 includes a display scene or real world set 110, a background/backdrop 114, and a foreground/floor 112. Physical objects (not shown), such as pieces of furniture that a “ghost” may walk among, may be provided on the floor/foreground 112 of the set 110. The assembly 100 also includes a large second space or room 120 that is reflected, when illuminated, into the real world set 110 by a beam combiner 130 as shown with reflected image 150.
A sheet or piece of glass (e.g., a beam splitter) 130 is positioned at an angle, θ, (e.g., 45 degrees) between the scene 110 and the expected or planned position of the viewer 105 (or the viewer's point of view (POV)) or an outer display surface/window. The beam combiner 130 may be glass or another transmissive/reflective material such as Mylar or the like and be supported in a frame 132. The beam combiner 130 is at least partially transparent such that the foreground 112 and the backdrop 114 are visible through the beam combiner 130 as light (shown as a display on a screen of an animated or still character 123) from a 3D display 122 (in this example) travels through the beam combiner 130 to the viewer or viewer's eyes 105. The display device 122, such as a typical 2D monitor, a 3D display, a physical object, or a hidden room/scene that can be selectively lit, is provided in the display assembly 100 and is used to display an image 150 such as the 3D virtual character shown in FIG. 1.
The Pepper's Ghost effect is highly popular and is an effective illusion for placing virtual objects in a real world scene. The technique often involves use of a half-silvered Mylar or glass plate mirror (also called a beam combiner as discussed above with reference to FIG. 1) to visually combine the reflection of a monitor and the pass-through view of the real world/physical set. Typically, a large beam combiner must be used such as one that is room sized so that the edges of the mirror and frame are off stage and not visible to viewers or a members of an audience.
As will be appreciated, the conventional Pepper's Ghost assembly design can be problematic for a number of reasons. The glass mirror or beam combiner has to be huge and thick (if unsupported) so that it is very heavy and may sag, thereby distorting the reflected image. In some cases, the mirror film may be relatively thin but must be held taut. Then, a frame that is opaque and visible has to be provided in the physical set. Also, the beam combiner or mirror effectively divides the physical set or real world room in two, which severely limits the physical space available to the effect designer as half the room or set space cannot be used (e.g., the space between the beam combiner a viewing glass (not shown in FIG. 1) separating the set from the viewer.
In practice, the weight, expense, and installation difficulty of conventional Pepper's Ghost assemblies can cause challenges. Further, the size of the mirror is often much larger than the effect or displayed virtual character itself. For example, the virtual character may only occupy a small area in the middle of the room-sized set. A room-sized beam splitter cuts the room in half, which prevents, in the case of an amusement park ride, the ride vehicle from traveling in a circuitous path around the room or set. This division by the beam combiner also interferes with set pieces or props. A second space that often matches the size of the real world or physical set is being reflected so when a large room-sized beam splitter is used in a Pepper's Ghost assembly the second space must be equally large even if the virtual character is relatively small (e.g., see smaller character 150 in large set 110 in FIG. 1). Smaller beam combiners are not used because you have to hide the frame and also the beam combiner edges from view in the real world set.
There remains a need for improved visual display techniques and systems such as for creating or projecting/displaying 3D images. Some attempts to replace or modify conventional Pepper's Ghost assemblies have been proposed, but these only provided 2D or flat images and include display elements that were readily visible to the viewer, which harmed the illusion.